Do you get hives just saying the "Z" word?
Maybe I can help!
Keep reading....Step 1: Using a basting stitch, make a seam where your zipper is to go. Finish the rest of the seam with a regular stitch length, back stitching at both ends.
Step 2: Press the seam open. Lay your zipper face down onto the seam. (If your zipper is longer than you need, you can shorten it by making a little thread stop, like I did below, and then cut off the extra length.)
Step 3: Unzip the zipper completely and pin one side of the zipper tape onto the open seam being sure that the teeth of the zipper are centered over the center of the seam.(Note: You are pinning it to the seam allowance only!)
Step 4: Using a zipper foot, baste the zipper tape (that you just pinned) onto the seam allowance, as shown below. Please notice that you are not stitching through to the front of the garment....just to the side of the open seam.
Step 5: Now, close the zipper and look for a roll of scotch tape! Lay the garment out flat and tape the zipper down as well as you can. (I used green washi tape to demonstrate so that you can better see how to do this. Since you will be sewing through the tape, I think scotch tape works better for this step, however.)
Step 6: Turn the garment to the right side and stitch evenly on both sides of the closed seam, catching the zipper as you sew. The zipper foot allows you to get close to the zipper teeth. I try to stitch about 1/4 inch from the seam line on both sides, stitching across the bottom of the zipper.
Step 7: You are almost finished.....Take your seam ripper and carefully remove the previously basted center seam, being careful not to cut the fabric. (You will need to pull out the basting threads. If you are really clever, and used a long enough stitch, you may even be able to pull it all out in one piece!)
Remove the tape. BAM! You're done!